Electrostatic discharge (ESD) events may involve a sudden flow of electricity between two electrically charged objects caused by contact, an electrical short, or a dielectric breakdown. When an ESD event occurs, an accumulation of charge from the sudden flow of electricity may generate an ESD voltage that may peak at a relatively high level, which may cause damage to electronic circuits. Electronic devices may include ESD protection circuitry to protect against the harmful effects of ESD events.
Some ESD protection circuits may protect against ESD events by discharging charge generated during an ESD event in order to suppress the ESD voltage to safe levels. In addition, some ESD protection circuits may utilize a timing window to initially detect an ESD event. The timing window may be relatively short so that the ESD protection circuit can differentiate an ESD event from other transient events that do not change as rapidly and that should not be suppressed. A timing window may also be used to determine how long the ESD protection circuitry is to discharge charge if an ESD event is detected. The timing window used for detection may be too small to set the duration of discharge. At the same time, using additional circuitry to set a second timing window for discharge may require a delay between detection and discharge, which in turn may cause an initial portion of the ESD voltage to be inadequately suppressed since ESD events happen so quickly. ESD protection circuitry that adequately suppresses ESD voltage as early as possible and over as long of a duration of the ESD event as possible may be desirable.